Yard Trimmings

In most communities in California,
residential yard trimmings make up 15 to 30 percent of the total residential
waste stream. Although some major seasonal fluctuations occur in most areas,
this waste stream is produced year-round in most of California. Recognizing
the significance of yard trimmings, 294 communities (56 percent of the total
in the state) had implemented some type of yard trimmings recycling program.
In 1994, another 28 (9 percent) had planned such programs.

Collection programs are typically provided weekly or biweekly to
customers to obtain the maximum participation. Unlike curbside recycling
materials, residents generate yard trimmings on a sporadic basis when they
are able to tend to their gardens, lawns, and pruning. Residents who do not
participate every week benefit from having more frequent service when they
want it.

Residents are usually asked to set their yard trimmings out in the
following containers:

Cans

Bags

Rolling carts

Unbundled, in the street

The least expensive system often uses existing garbage cans for yard
trimmings collection (sometimes with a decal or a sticker to label the can
provided by the community).

In Monterey Park, Calif., for example, yard trimmings must be set out in
permanent containers marked with a special yard trimmings sticker or tied in
bundles under 4 feet in length. Containers must be turned so stickers are
visible to drivers.

Stickers can be obtained from the local waste hauler (Athens Services) or
in person at city hall public counters. Yard trimmings are usually collected
in the early afternoon, after the trucks have finished collecting refuse.
Yard trimmings must not be contaminated with refuse or recyclables, or they
are collected as trash.

Some communities allow residents to place yard trimmings at the curb in
plastic or paper bags. Although plastic bags are a contaminant in processing
at composting facilities, these communities have decided the convenience of
this approach is worth the cost to separate the plastics. Other communities
have experimented with providing biodegradable plastic or paper bags to
residents. These approaches are generally more costly and have not been
widely adopted.

The majority of the most successful programs are providing rolling carts
or collection services unbundled on the street. Rolling carts have become
more prevalent through the 1990s for the collection of yard trimmings.

Carts offer the advantage of collection with automated or semi-automated
collection equipment. This decreases worker injuries and workers’
compensation claims for the haulers. Carts are also attractive to residents
who do not have a lot of yard trimmings weekly, because the material is
easily contained and rolled to the curb.

Carts have a significant additional attraction for the future. Carts lend
themselves to the addition of discarded foods and food-contaminated paper.
Carts are the best of all home storage containers for these additional
organics to be collected together with yard trimmings. The examples below
show how this can help communities increase organics recycling.

In San Jose, unbundled yard trimmings are collected with the “claw”
attachment on a loader and placed in the back of a rear-loader packer truck.
A major advantage of this approach is that residents do not have to cut yard
trimmings into small pieces and don’t have to place yard trimmings into
containers to recycle them. The results have proven very popular in San
Jose, as in other communities that have used this approach.

In the City of Sacramento, the public actually voted two to one in a
public referendum in the early 1990s to maintain the yard trimmings
collection program there. That program operated for many years using the
same collection approach as San Jose. People loved the convenience of the
program for their gardening and yard work.

A typical example of yard trimmings collection programs are those
provided by the City of Riverside. Unlike most communities in California,
Riverside initiated its IWMA programs with its green waste collection
program in 1992. The city focused on green waste first, because that was the
major material identified in its waste characterization study.

Riverside shifted from twice-a-week collection of trash to once-a-week
collection of trash and once-a-week collection of green waste. Green wastes
are placed in a green automated collection container. The green waste is
delivered and tipped at a $20-per-ton savings when compared to trash. For
the 1998-99 fiscal year, the residential green waste collectors were able to
divert 42 percent of the material collected from landfills. This resulted in
a savings of $856,427 in disposal fees.

One of the early concerns about different program designs was ensuring
that a quality product could be produced from yard trimmings collected
broadly from residents. Experience during the 1990s has shown that all of
the above collection programs have been able to produce quality compost
feedstock.

The key to obtaining good feedstock is proper enforcement of good
preparation requirements and monitoring of yard trimmings as they are
collected on the street. In many communities, collectors leave behind
improperly prepared material with a note to educate residents on proper
preparation for the future.

Processing of residential yard trimmings is often done by local
composting facilities or by shredding at landfill sites for alternative
daily cover (ADC). Throughout the 1990s, the issue of ADC has been a concern
to composters. If landfills accept yard trimmings for tipping fees that are
lower than composting facilities in the area, communities are able to save
money. However, by accepting yard trimmings for lower tipping fees,
landfills make it much less economic for composters to operate.

The counting of ADC as “recycling” was originally adopted by the CalRecycle as
an interim policy to assist communities until stronger markets could be
developed (for example, in the agricultural sector).

Communities could contribute to expanding markets by buying compost and
mulch products and by requiring public and private developments to use those
products (see “community procurement” on page 13). However, Chapter 978,
Statutes of 1996 (AB 1647, Bustamonte), codified the ADC credit into law as
an ongoing option for diversion credit under the IWMA.

Most communities collect Christmas trees after
the holidays as part of their solid waste services. Most programs offer both
curbside and drop-off locations. Drop-off locations are particularly well
designed for Christmas trees, because it is often easier to drop off trees
than to cut them up into smaller sizes needed to comply with yard trimmings
collection programs.

Because most of these trees are uncontaminated (except those flocked or
left covered with tinsel), many communities have found that they can recycle
these trees into valuable compost and mulch products.

In San Diego, Christmas tree recycling has been operating since 1973,
organized by I Love a Clean San Diego. Since 1982, the City of San Diego has
supported the effort as well. In 2000, the city had 31 drop-off sites.

Hosts for the drop-off sites included shopping centers, parks, open
spaces, vacant lots, community centers, schools, tree nurseries, and city
facilities. The city also collected trees through its curbside yard
trimmings recycling collection program.

More than 130,000 trees were collected from the drop-off sites and 11,000
from the curbside program, for a total of 141,800 trees. All of the trees
were ground into mulch and compost at the city’s Miramar “Greenery” as soon
as they arrived on-site. Curbside collected trees were put through a trommel
before grinding to remove contamination (this was unnecessary for trees
dropped off).

The trees not only enhance the smell of the mulch, but they also slightly
increase the acidity. This makes the mulch very useful to residents in the
area with alkaline soils, which are commonly found in San Diego. Mulch is
distributed free to residents.

The City of San Diego diverted 84 percent of all Christmas trees from
landfilling, disposing only of the flocked and tinseled trees. This was
determined by actual tree counts, a curbside participation study, and
tonnages from the Miramar Landfill. A conversion factor of 17 pounds per
tree was used to convert tonnage data to the number of trees recycled.

The operational costs incurred for this program are part of the normal
yard trimmings collection budget for residents. The only additional costs
incurred are in advertising, including 70,000 flyers, 700 posters,
production of a movie theater slide, and new signs and banners for drop-off
sites.

In addition, the program included a media kickoff event, and coordinators
produced 30-second video public service announcements (PSAs) for all TV
stations in San Diego. They also provided radio interviews and radio PSAs.
News releases went to church and business newsletters and to other media
promoting Christmas tree recycling and how to have a no-waste holiday.
Program staff operated a Christmas Tree Hotline that received 6,112 calls.

Many developments with large landscaped areas are developing their own
composting programs on-site. These include parks, golf courses, corporate
campuses, colleges and universities, and large multifamily residential
developments.

In areas where adequate space is available, chipping and mulching or
windrow composting may be done on-site. In other areas that are more densely
developed, new commercial on-site composting systems are being used (see
examples below under commercial discarded food).

In many areas, independent landscapers are still responsible for
maintaining the properties and collecting the yard trimmings. Landscapers
take their materials to competitive composting facilities wherever they are
available.

In San Jose, the Villages Golf and Country Club has been operating an
outstanding yard trimmings composting program for many years. They collect
grass clippings, weeds, and tree prunings from routine landscape maintenance
activities. They grind these materials into particles 1 to1½ inches in size.
They compost these materials in windrows, which take 90 to 120 days for a
final product. This reduces the volume of incoming materials by 65 to 70
percent.

The Villages facility uses the end product as a soil conditioner,
fertilizer, and a suppressor of soil-borne diseases (by increasing the
biological activity in the soil). Compost is used as a top dressing for
lawns, dug into garden beds for vegetables and flowers, spread as mulch
around bushes and shrubs, backfilled in planting holes, and spread between
rows of plants.